Core D: The imaging of airway epithelia is crucial to understanding the function and control of airway surface liquid in both health and disease. The Imaging Core will provide the skills and resources necessary to fix, embed, stain and image tissues and cells, or stain and image live tissues for light and electron microscopy. An extensive range of standard microscopy techniques will be made available. Hence, the Core will enable the localization by immunostaining of CFTR, ENaC, and proteases of interest created by the projects, track and assess lipids and vesicle trafficking in live tissues, and measure airway surface liquid levels on cultured tissue models. Imaging Core resources will be used by the Core personnel as a service to project participants, and optical equipment and general image analysis users will be trained by the Core personnel in the proper and knowledgeable use of specific equipment. Consultation on tissue preparation, staining, image acquisition and analysis will be provided. Core personnel will assist project investigators improve and develop standard and new techniques, trouble shoot problems, and help ensure that results are interpreted meaningfully. Relevance to public health: The Imaging Core provides high performance microscopy to the research projects in terms of acquisition, analysis and interpretation.